Novel brain-penetrant inhibitor of G9a methylase blocks Alzheimer’s disease proteopathology for precision medication
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ABSTRACT: we developed a novel brain-penetrant inhibitor of G9a, MS1262, across the blood-brain barrier to block this G9a-regulated, proteopathologic mechanism. Intermittent MS1262 treatment of multiple AD mouse models consistently restored both cognitive and noncognitive functions to healthy levels. Comparison of proteomic/phosphoproteomic analyses of MS1262-treated AD mice with human AD patient data identified multiple pathological brain pathways that elaborate amyloid beta and neurofibrillary tangles as well as blood coagulation, from which biomarkers of early stage of AD including SMOC1 were found to be affected by MS1262 treatment.
Project description:Current amyloid beta-targeting approaches for Alzheimer’s disease (AD) therapeutics only slow cognitive decline for small numbers of patients. This limited efficacy exists because AD is a multifactorial disease whose pathological mechanism(s) and diagnostic biomarkers are largely unknown. Here we report a new mechanism of AD pathogenesis in which the histone methyltransferase G9a noncanonically regulates translation of a hippocampal proteome that defines the proteopathic nature of AD. Accordingly, we developed a novel brain-penetrant inhibitor of G9a, MS1262, across the blood-brain barrier to block this G9a-regulated, proteopathologic mechanism. Intermittent MS1262 treatment of multiple AD mouse models consistently restored both cognitive and noncognitive functions to healthy levels. Comparison of proteomic/phosphoproteomic analyses of MS1262-treated AD mice with human AD patient data identified multiple pathological brain pathways that elaborate amyloid beta and neurofibrillary tangles as well as blood coagulation, from which biomarkers of early stage of AD including SMOC1 were found to be affected by MS1262 treatment. Notably, these results indicated that MS1262 treatment may reduce or avoid the risk of blood clot burst for brain bleeding or a stroke. This mouse-to-human conservation of G9a-translated AD proteopathology suggests that the global, multifaceted effects of MS1262 in mice could extend to relieve all symptoms of AD patients with minimum side effect. In addition, our mechanistically derived biomarkers can be used for stage-specific AD diagnosis and companion diagnosis of individualized drug effects.
Project description:N6-methyladenosine (m6A) modification pathway is hijacked by several RNA viruses, including SARS-CoV-2, making it an attractive host-directed target for development of broad-spectrum antivirals. Here, we show that histone methyltransferase G9a, through its interaction with METTL3, regulates SARS-CoV-2 mediated rewiring of host m6A methylome to ultimately promote turnover, abundance, secretion and/or phosphorylation of various viral receptors and proteases, transcription factors, cytokines/chemokines, coagulation & angiogenesis associated proteins, and fibrosis markers. More importantly, drugs targeting G9a and its associated protein EZH2 are potent inhibitors of SARS-CoV-2 replication and reverse multi-omic effects of coronavirus infection in human alveolar epithelial cells (A549-hACE2) and COVID-19 patient PBMCs - with similar changes seen in multiorgan autopsy samples from COVID-19 patients. Altogether, we extend G9a function(s) beyond transcription to translational regulation during COVID-19 pathogenesis and show that targeting this master regulatory complex represents a new strategy (drug-class) that can be leveraged to combat emerging anti-viral resistance and infections.
Project description:G9a (EHMT2) and the G9a-like protein GLP (EHMT1) form a stable G9a/GLP heterodimer in embryonic stem cells and function cooperatively to establish and maintain the abundant repressive H3K9me2 modification, in addition to modifying several non-histone proteins. The G9a-dependent H3K9me2 is implicated in lineage-specific gene silencing and covers large chromosomal domains. While the mechanism of H3K9me2maintenance by G9a/GLP is known, how new patterns of this modification are established is not well understood. With this in mind, we used FLAG affinity purification of G9a under two different stringency conditions (150 and 300 mM NaCl) coupled with mass spectrometry to identify proteins stably associated with G9a/GLP, which could serve as potential recruiters of the complex to unmodified chromatin.
Project description:Gene expression in eukaryotes is tightly linked to the methylation state of specific lysine residues within the N-terminal region of the core histone proteins. While the mechanisms connecting histone lysine methylation to effector protein recruitment and control of gene activity are increasingly well understood, it remains unknown whether non-histone chromatin proteins are targets for similar modification-recognition systems. Here we show that histone H3 and the H3 methyltransferase G9a share a conserved methylation motif that is both necessary and sufficient to mediate in vivo interaction with the potent epigenetic regulator Heterochromatin Protein 1 (HP1). As with H3, G9a-HP1 interaction is dependent on lysine methylation and can be reversed by adjacent phosphorylation. NMR analysis demonstrates that the HP1 chromodomain recognizes methyl-G9a through a binding mode similar to that used in recognition of methyl-H3, and that adjacent phosphorylation directly antagonizes G9a-HP1 interaction. In addition to uncovering the chromodomain as a generalized methyl-lysine binding module, these data identify histone-like modification cassettes (or âhistone mimicsâ) as an entirely new class of non-histone methylation targets, and directly demonstrate the relevance of the principles underlying the histone code to the regulation of non-histone proteins. Experiment Overall Design: Two independent Affymetrix gene expression microarray analyses were performed on samples from G9a-deleted MEFs reconstituted with empty vector (delta), wild type FLAG-G9a (WT), FLAG-G9a K165A (K165A) or FLAG-G9a H1093K catalytic mutant (H1093K).
Project description:modENCODE_submission_5611 This submission comes from a modENCODE project of Gary Karpen. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: We aim to determine the locations of the major histone modifications across the Drosophila melanogaster genome. The modifications under study are involved in basic chromosomal functions such as DNA replication, gene expression, gene silencing, and inheritance. We will perform Chromatin ImmunoPrecipitation (ChIP) using genomic tiling arrays. We will initially assay localizations using chromatin from three cell lines and two embryonic stages, and will then extend the analysis of a subset of proteins to four additional animal tissues/stages. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf EXPERIMENT TYPE: CHIP-chip. BIOLOGICAL SOURCE: Strain: G9a mutant (official name : G9a mutant genotype : G9a[RG5]/G9a[RG5] outcross : 3 transgene : n/a tags : homologous recombination tag : none description : Mutation generated by end-out homologous recombination at the G9a locus. The entire open reading frame of G9a has been removed. Developmental Stage: 3rd Instar Larvae; Genotype: G9a[RG5]/G9a[RG5]; Transgene: n/a; NUMBER OF REPLICATES: 4; EXPERIMENTAL FACTORS: Strain G9a mutant (official name : G9a mutant genotype : G9a[RG5]/G9a[RG5] outcross : 3 transgene : n/a tags : homologous recombination tag : none description : Mutation generated by end-out homologous recombination at the G9a locus. The entire open reading frame of G9a has been removed. Antibody H3K9me3 abcam (target is H3K9me3); Developmental Stage 3rd Instar Larvae
Project description:modENCODE_submission_5615 This submission comes from a modENCODE project of Gary Karpen. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: We aim to determine the locations of the major histone modifications across the Drosophila melanogaster genome. The modifications under study are involved in basic chromosomal functions such as DNA replication, gene expression, gene silencing, and inheritance. We will perform Chromatin ImmunoPrecipitation (ChIP) using genomic tiling arrays. We will initially assay localizations using chromatin from three cell lines and two embryonic stages, and will then extend the analysis of a subset of proteins to four additional animal tissues/stages. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf EXPERIMENT TYPE: CHIP-chip. BIOLOGICAL SOURCE: Strain: G9a mutant (official name : G9a mutant genotype : G9a[RG5]/G9a[RG5] outcross : 3 transgene : n/a tags : homologous recombination tag : none description : Mutation generated by end-out homologous recombination at the G9a locus. The entire open reading frame of G9a has been removed. Developmental Stage: 3rd Instar Larvae; Genotype: G9a[RG5]/G9a[RG5]; Transgene: n/a; NUMBER OF REPLICATES: 4; EXPERIMENTAL FACTORS: Strain G9a mutant (official name : G9a mutant genotype : G9a[RG5]/G9a[RG5] outcross : 3 transgene : n/a tags : homologous recombination tag : none description : Mutation generated by end-out homologous recombination at the G9a locus. The entire open reading frame of G9a has been removed. Antibody H3K36me3 abcam (target is H3K36me3); Developmental Stage 3rd Instar Larvae
Project description:Purpose: The aim of this study is to compare brain transcriptome profile (RNA-seq) after G9a inhibition. Methods: Hippocampus profiles of 7-month-old SAMP8 Control and SAMP8 Treated mice groups were generated by deep sequencing, pooled using Ilumnia Hiseq. Results: G9a inhibition with UNC0642 induces a transcriptional profile that allows beneficial effects on cognitive performance. Differential expression analysis identified 697 differentially expressed genes (DEG) (fold change cutoff of ≥1.3, p-value<0.05). Of which 217 are reduced, and 480 are increased in SAMP8 UNC0642. Conclusions: Our study showed the first transcriptome analysis of whole brain after G9a inhibition, generated by RNA-seq technology, demonstrating transcriptomic changes.
Project description:Purpose: The aim of this study is to compare brain transcriptome profile (RNA-seq) after G9a inhibition. Methods: Hippocampus profiles of 7-month-old SAMP8 Control and SAMP8 Treated mice groups were generated by deep sequencing, pooled using Ilumnia Hiseq. Results: G9a inhibition with UNC0642 induces a transcriptional profile that allows beneficial effects on cognitive performance. Differential expression analysis identified 697 differentially expressed genes (DEG) (fold change cutoff of ≥1.3, p-value<0.05). Of which 217 are reduced, and 480 are increased in SAMP8 UNC0642. Conclusions: Our study showed the first transcriptome analysis of whole brain after G9a inhibition, generated by RNA-seq technology, demonstrating transcriptomic changes.
Project description:G9a depleted SKCO3 cells were used to identify genes regulated by G9a-dependent epigenetic regulations We used microarrays to detail the global programme of gene expression underlying paritoneal dissemination and identified distinct classes of G9a-regulated genes during this process. SKOV3 cells receiving G9a-specific shRNAs were analyzed compare to cells receiving control shRNA
Project description:The role of the histone methyltrasferase G9a (also known as Ehmt2) in the normal heart has not been studied extensively. To identify the genomic regions bound to G9a in cardiomyocytes (CMs),we first generated a conditional, cardiac-specific KO mouse for this gene using the Cre-Lox approach, crossing G9a flox/flox mice with αMHC-MerCreMer mice (Cre mice were used as controls). Then we performed ChIP-seq for G9a and H3K9me2 – the main histone methylation catalysed by the HMT – on isolated G9a-KO and Cre CMs, and considered the best G9a-bound genomic regions as those that had a loss or decrease of G9a binding as well as a lower level of H3K9me2 in G9a-KO CMs. Since G9a contributes to trimethylation of H3K27 at a set of developmental genes through its interaction with PRC2, we also evaluated whether the loss of G9a had an effect on the distribution of this histone mark. To this end, we performed ChIP-seq for H3K27me3 in Cre CMs and G9a-KO CMs. Finally co-immunoprecipitation assays revealed that G9a interacts with Mef2c, thus to elucidate the function of the G9a–Mef2c interaction in adult cardiomyocytes, we used ChIP-seq to define the genomic distribution of Mef2c in Cre CMs and G9a-KO CMs.